Limit cache invalidation by the updated source bounds.

pkg/analyzer/lib/src/generated/incremental_resolver.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library engine.incremental_resolver;
 
 import 'dart:collection';
 import 'dart:math' as math;
 
 import 'package:analyzer/src/context/cache.dart'
-    show CacheEntry, Delta, DeltaResult, TargetedResult;
+    show CacheEntry, Delta, DeltaResult;
 import 'package:analyzer/src/generated/constant.dart';
 import 'package:analyzer/src/task/dart.dart';
 import 'package:analyzer/task/dart.dart';
 import 'package:analyzer/task/general.dart' show CONTENT, LINE_INFO;
 import 'package:analyzer/task/model.dart'
     show AnalysisTarget, ResultDescriptor, TargetedResult, TaskDescriptor;
 
 import 'ast.dart';
 import 'element.dart';
 import 'engine.dart'
@@ skipping 828 matching lines @@
    */
   final int updateDelta;
 
   IncrementalBodyDelta(Source source, this.updateOffset, this.updateEndOld,
       this.updateEndNew, this.updateDelta)
       : super(source);
 
   @override
   DeltaResult validate(InternalAnalysisContext context, AnalysisTarget target,
       ResultDescriptor descriptor) {
+    // A body change delta should never leak outside its source.
+    // It can cause invalidation of results (e.g. hints) in other sources,
+    // but only when a result in the updated source is INVALIDATE_NO_DELTA.
+    if (target.source != source) {
+      return DeltaResult.STOP;
+    }
     // don't invalidate results of standard Dart tasks
     bool isByTask(TaskDescriptor taskDescriptor) {
       return taskDescriptor.results.contains(descriptor);
     }
     if (descriptor == CONTENT) {
       return DeltaResult.KEEP_CONTINUE;
     }
     if (target is LibrarySpecificUnit && target.unit != source) {
       if (isByTask(GatherUsedLocalElementsTask.DESCRIPTOR) ||
           isByTask(GatherUsedImportedElementsTask.DESCRIPTOR)) {
@@ skipping 1250 matching lines @@
   @override
   String toString() => name;
 }
 
 class _TokenPair {
   final _TokenDifferenceKind kind;
   final Token oldToken;
   final Token newToken;
   _TokenPair(this.kind, this.oldToken, this.newToken);
 }